Method of removing carbon deposits from internal-combustion engines



.engine under United States Patent METHOD OF REMOVING CARBON DEPOSITSFROM INTERNAL-COMBUSTION ENGINES 'No Drawing. Application December 15,

Serial No. 201,061

3 Claims. (Cl. 134-7) The present invention .relates to .a method ofremoving dep i from th combustion chambers of internal combustionengines in a simple .and effective manner.

It is well known that deposits quickly accumulate in the. combustionchamber of internal combustion engines such as those used inautomobiles. An engine with deposits requires the use of agasoline witha higher octane rating than .does a clean engine if the engine is not toknock, and the .dirty engine is said to have a higher octane demand.This becomes apparent to the driver of an old automobile ,by theknocking of the engine while accelerating, climbing ,a hill or otherwiseoperating the greater than normal load. The deleterious effects of suchaccumulations of deposits is particularly noticeable in engines having.a high compression ratio because the margin between the octane numberof gasolines on the market and. the octane demand of the engine whenclean is narrower than for engines having lower compression ratios.

A great number of methods have been proposed heret fore for cleaning thecombustion chambers of an internal combustion engine. One of thesemethods is that of introducing a liquid solvent into the carburetorwhile the engine is running. Although this method produces great bellowsof smoke at the exhaust, it has been found, upon taking an engine sotreated apart after the operation, that little of the deposits areactually removed.

Another of these methods is that of inserting particles of metal orother objects such as chains and the like into the various cylindersthrough the spark plug holes, replacing the spark plug, running theengine, and then removing the chains or connected particles if such wereused. This method of operation, where discrete particles of metal wereused, has been found entirely impracticable because (a) the particleseither melt, due to the heat of combustion, before the engine gainssufficient speed to impart to the particles a velocity high enough toremove deposits upon impact therewith or, if the particles do not melt,they are so hard and non-crushable as to cause injury to the engine ifjammed between moving parts such as a valve head; (12) the number ofparticles introduced into each cylinder at one time is either so greatas to interfere seriously with the combustion and the movement of thevalves and piston, or so small that the spark plug for each cylinderwill have to be removed and replaced so often during a single cleansingas to make excessive the time required for the operation and theprobability of injury to the spark plugs; and (0) many of the particlesroll out through the valves before the engine gains sufiicient speed tomake them effective, thus resulting in a waste of particles and in anaccumulation thereof in the exhaust manifold and muffler.

In view of the failure of the many proposed methods, of which theforegoing are but a few, it is still standard Practice to clean aninternal combustion engine by removing the head and grinding thedeposits away from the tops ofthe pistons and valves and the recesses inthe cylinder head forming the confining surfaces of the combustionchamber. This method is expensive and time consuming and renders theengine useless for at least a day.

A method for removing the deposits in the combustion chambers of aninternal combustion engine has now been found that does not require alifting of the cylinder head, is not injurious to the engine, isextremely inexpensive and requires very little time. In essence, thismethod involves introducing substantially continuously and uniformly,over an extended period of time, into the intake manifold for tion ofpinches of say conveyance to and substantially equally distributionamong the engine cylinders while the engine is running, a plurality ofdiscrete .particleshaving a melting point above about 3100" C. and a BHN(Brinell hardness number) between about 3 and 1:15.

The size of the individual articles that may be used in accordance withthe .method of this. invention is limited only'by the minimum clearancein the combustion chamber between the piston and the cylinder head whenthe piston is at the .top of itsstroke. For automobile engines it isusually desirable that the maximum dimension of any particle should notexceedabout 0.125 For engines Thavmg a larger piston displacement,suchas truck engnes, the maximum dimension of the particles may be ashigh as 0.'25".. The minimum dimension of the particles shouldordinarily not be less than about 0.05", the reason being that particleshaving a smaller minimum dimension tend -to lose their cleansingeffectiveness quickly because of more rapid melting as well as lowerkinetic energy.

The particlesmay have anydesired shape suchas cubes, cylinders,ellipsoids, spheres and the like. One type of particle which has beenfound to be particularly effective is a flattened sphere having amaximum dimension of approximately 0.125" and minimum dimension of 0.09.Another shape that is particularly desirable from an economical point ofview is the unflattened sphere. This makes it possible to use goods,such as ordinary lead-shot, now available on the market.

The particles should be hard enough, under the hightemperatureconditions prevailing in the combustion chamber of an internalcombustion engine, to chip carbonaceous and other deposits off the wallsof the combustion chamber upon impact therewith and yet be sufiicientlycrushable to avoid injury to the engine if jammed between two movingparts or between a stationary and a moving part. Tests have indicatedgenerally that particles having a BHN between about 3 and aresatisfactory. This includes particles of metals such as aluminum, lead,magnesium, 'zinc, cadmium, copper and many of the alloys of said metals,as well as some very soft irons, such as malleable or ingot iron and lowcarbon steel as Well as particles of said metals and harder metals in asintered condition.

It has been found that particles of sintered metals are particularlyeffective. Such particles are made by compressing the one or moreconstituent metal powders followed by a heat treatment at a temperaturebelow their melting point. This process results in particles havingconsiderable porosity which renders them more crushable and consequentlypermits the use of metals that would otherwise be too hard.

The method of the invention is most effectively carried out byintroducing the particles into the engine through the carburetor withthe air filter removed. This is accomplished by pour'ing the particlesin a steady stream or in fairly uniform increments into the carburetorpast the butterfly valve While the engine is run at a fairly high speed.This is preferably carried out in such a manner that approximately 50 to250 particles per cylinder are introduced within approximately 1 to 10minutes or at an over-all rate of between about 5 and 50 particles perminutes per cylinder.

The introduction of the particles can be accomplished by means of asuitable dispenser or by the continual addiabout 5 to 20 particles each,care being taken to avoid having more than three or four particles ineach cylinder at any given time so that the operation wiil not becometoo noisy.

The advantages of this method of cleaning an internal combustion engineare numerous. The method is extremely simple and may be carried out inless time than it takes to have the oil changed. As will be brought outin the examples hereinafter, the method is effective in reducingconsiderably the octane demand of a dirty engine. It does not require alifting of the cylinder head or even the removal of the spark plugs. Dueto the method of introduction of the particles through the intakemanifold and their cooling in the manifold by contact with the mixtureof air and vaporizing fuel droplets under subatmospheric pressure, it ispossible to use particles of metals that would otherwise melt within thecombustion chamber before they could be sufliciently agitated to removecarbonaceous deposits upon impact therewith.

Extensive tests have shown that the introduction of particles of metalinto an engine in accordance with the method of this invention resultsin no perceptible injury to any part of the engine. The engines in twoheavy-duty trucks that were subjected to periodic cleaning by the methodof this invention showed, upon being taken down after 90,000 miles oftravel each, no preceptible signs of damage to any of the engine partsincluding the valves, cylinder heads, pistons, cylinder walls, andbearings.

EXAMPLE 1 A total of six tests were carried out with three automobileengines, a Chevrolet, a Ford and a Plymouth. These engines were selectednot only because they are representative of a high percentage of theautomobile engines in use at the present time, but also because theintake manifolds are quite different from one another.

In each test the air filter was first removed from the carburetor and,while the engine was in operation, approximately 100 pellets percylinder of sintered 80% copper, 20% lead, the pellets being flattenedspheres having a maximum dimension of 0.125, and a minimum dimen sion of0.090, were introduced within an interval of about five minutes on eachside of the butterfly valve in the throat of the carburetor.

The results are tabulated immediately below:

After each test, except test No. 2, the engine was taken apart toevaluate the efliciency of the carbon removal as well as any damage tothe engine parts. The carbon removal was found to be uniformly good asmight have been expected from the reported reduction in octane demand ofthe engine as a result of the cleaning operation.

It was found that in all engines parts of the pulverized pellets workedpast the pistons and rings into the oil pan and that some flakes werefound deposited on the bearings. Continued and extensive runningrevealed no damage due to the flakes on the bearings as these finallyworked out and fell to the bottom of the oil pan where they were eitherdeposited in the heavy sludge or drained away with the fluid sludge. Noactual damage of any kind was observed in any test.

The third test with the Chevrolet engine was carried out immediatelyafter the second test without taking the engine apart in the meantime.The failure, in the third test, to further reduce the octane requirementof the engine showed that the engine had been cleaned as much as itcould be in the second test. The examination of the engine after thethird test showed that even when an excessive number of pellets isintroduced into the engine, there is little danger of damage. Theexcellent results shown with the Plymouth engine n tests 5 and 6revealed that the method of this invention is effective even in engineswherein the materials introduced into the carburetor must be carriedupwardly through the intake manifold to reach the combustion chambers.In each instance overhaul of the engines subsequent to the testsrevealed very good distribution and cleaning of all cylinders.

EXAMPLE 2 Two further tests were carried out with standard sixcylinderChevrolet automobile engines. The procedure in each test wassubstantially the same as described in Example 1, but the composition,shape and dimensions of the particles were somewhat different. In testNo. 7, the particles consisted of /s clippings from an aluminum rodhaving a BHN of 16 and a diameter of A3". In test No. 8 the particlesused were chilled lead shot (an alloy having a BHN of 5 to 6) having adiameter of 0.09".

The results are tabulated immediately below:

It is apparent from the foregoing results that a considerable reductionin the octane demand of a dirty engine is obtained by the method of thisinvention. Upon dismantling the engine after test No. 7, it was foundthat several aluminum particles of different sizes remained, showing aprogressive chipping off of the aluminum particles. Only a trace of thelead shot charge was found after test No. 8 and in neither case wasthere any perceptible sign of damage to the engine.

In addition to the particles specifically described in the foregoingexamples, tests were also carried out with particles of commerciallypure copper, a sintered bearing mix consisting of 8% tin, 4% lead and88% copper, a sintered mix consisting of 70% copper and 30% lead and asintered mix consisting of copper and 40% lead, these particles havingthe shape and dimensions of the particles referred to specifically inExample 1.

It is apparent that many variations and modifications will occur tothose skilled in the art upon reading the above description. All suchvariations and modifications are intended to be included within thescope of this invention as defined within the appended claims.

I claim:

1. A method of removing deposits from the combustion chambers of aninternal combustion engine which comprises introducing, over an extendedperiod of time, into the intake manifold for conveyance to andsubstantially equal distribution among the engine cylinders while theengine is running, a plurality of pellets of metal having a meltingpoint above about 300 C. and a Brinell hardness number between about 3and 115.

2. A method of removing deposits from the combustion chambers of aninternal combustion engine which comprises introducing, over an extendedperiod of time, into the intake manifold for conveyance to andsubstantially equal distribution among the engine cylinders while theengine is running, a plurality of pellets of sintered metal having amelting point above about 300 degrees C. and a Brinell hardness numberbetween about 3 and 115.

3. A method of removing deposits from the combustion chambers of aninternal combustion engine which comprises introducing, over an extendedperiod of time, into the intake manifold for conveyance to andsubstantially equal distribution among the engine cylinders while theengine is running, a plurality of pellets of sintered copper and lead,said pellets having a melting point above about 300 degrees C. and aBrinell hardness number between about 3 and 115.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,034,713 Johnston Aug. 6, 1912 1,813,289 Hastings July 7,1931 1,916,506 Zubaty et a1. July 4, 1933 1,924,704 Bartholomew Aug. 29,1933 2,251,988 Curran Aug. 12, 1941 2,313,730 Boesing Mar. 16, 1943

1. A METHOD OF REMOVING DEPOSIT FROM THE COMBUSTION CHAMBERS OF ANINTERNAL COMBUSTION ENGINE WHICH COMPRISES INTRODUCING, OVER AN EXTENDEDPERIOD OF TIME, INTO THE INTAKE MANIFORD FOR CONVEYANCE TO ANDSUBSTANTIALLY EQUAL DISTRIBUTION AMONG THE ENGINE CYLINDERS WHILE THEENGINE IS RUNNING, A PLURALITY OF PELLETS OF METAL HAVING A MELTINGPOINT ABOVE ABOUT 300* C. AND A BRINELI HARDNESS NUMBER BETWEEN ABOUT 3AND 115.